1. Field of the Invention
The present invention relates to an image reading apparatus for obtaining a video signal from an image by means of a solid-state imaging device.
2. Description of the Prior Art
Conventionally, the output signal level from a solid-state imaging device such as a charge coupled device (CCD) is subject to variations, even for a determined light intensity, due to an increase in dark current resulting from an increase in the ambient temperature, a gain regulation in the video amplifying circuit and fluctuations between imaging devices.